LVFFARK conjugation to poly (carboxybetaine methacrylate) remarkably enhances its inhibitory potency on amyloid β-protein fibrillogenesis

摘要

Fibrillar aggregation of amyloid beta-protein (A beta) is complicated in the pathological process of Alzheimer's disease (AD). Therefore, inhibition of A beta aggregation is considered as a promising strategy for the precaution and treatment of AD. Ac.LVFFARK-NH2 (LK7) has been recognized as an inhibitor of A beta aggregation, but its propensity to aggregation and strong cytotoxicity limited its applications. Thus, we have herein conjugated LK7 to a zwitterionic polymer, poly (carboxybetaine methacrylate) (pCB), and synthesized three LK7@pCB conjugates of different degrees of substitution (DS). The conjugation eliminated the aggregation propensity of LK7 and the conjugates self-assembled into micelles. It revealed that the LK7@pCB micelles inhibited A beta fibrillogenesis and mitigated the amyloid cytotoxicity more efficiently than free LK7. Structural analysis indicated that LK7@pCB micelles suppressed the conformational transition of A beta(42) into beta-sheet structure and thus changed its aggregation pathway. The superiority of LK7@pCB is considered due to the integrated functions of LK7 and pCB. Namely, high local LK7 concentration in the micellar interior significantly enhanced the interactions between A beta(42) and LK7, and the dense hydration layer on pCB strongly stabilized the bound A beta on LK7 anchored on pCB, restricted its conformational transition and the following on-pathway fibrillation.